Comparing Pigments Practical

Question 1

What can is used to compare pigments in plants

Answer 1

TLC

Question 2

What is the first step to the comparing pigments practical

Answer 2

grind up several leaves from the shade tolerant plant your investigating with some anhydrous sodium sulfate then add a few drops of propanone

Question 3

What’s the second step to the comparing pigments practical

Answer 3

Transfer the liquid to a test tube add some petroleum ether and gently shake the tube. Two distinct layers will form in the liquid - the too layer is the pigments mixed in with the petroleum ether

Question 4

What’s the third step of the comparing pigments practical

Answer 4

Transfer some of the liquid from the top layer into a second test tube with some anhydrous sodium sulfate

Question 5

What’s the 4th step of the comparing pigments practical

Answer 5

Draw a horizontal pencil line near the bottom of a TLC plate. Build up a single concentrated spot of the liquid from step 3 on the line by applying several drops and ensuring each one is dry before the next is added. This is the point of origin.

Question 6

What is the fifth step of comparing pigments practical

Answer 6

Once the point of origin is completely dry , put the plate into a small glass container with some prepared solvent (e.g. a mixture of propanone, cyclohexane and petroleum ether) - just enough so that the point of origin is little bit above the solvent. Put a lid on the container and leave the plate to develop. As the solvent spreads up the plate, the different pigments move with it, but at different rates - so they separate.

Question 7

What is the sixth step of comparing pigments practical

Answer 7

When the solvent has nearly reached the top, take the plate out and mark the solvent front (furthest point the solvent has reached) with a pencil and leave the plate to dry in a well- ventilated place

Question 8

What is the seventh step in the comparing pigments practical

Answer 8

There should be several new coloured spots on the chromatography plate between the point of origin and the solvent front

These are the separated pigments. You can calculate their RF values and look them up in a database to identify what the pigments are

Question 9

What is the eighth step of the comparing pigments practical

Answer 9

Repeat the process for the shade intolerant plant your investigating and compare pigments present I. Their leaves